This proposal is a logical continuation of research which has been aimed primarily at increasing our knowledge of what is important in Cancer diagnosis and development of the logic for computer assisted diagnosis of tumors. The ultimate goal is improvement of the quality of cancer health care. This proposal continues the thread of previous research, broadening the scope of computer assisted programs for diagnosing bone cancer and related conditions and continues work already initiated on the direct computer diagnosis of bone cancer. Successfully carried out, this proposal will develop automated screening mechanisms for the radiologic diagnosis of cancer, will sharpen our ability to teach and to communicate about the diagnosis of cancer, and will provide insight into the natue of missed diagnosis. If our experience with the direct computer diagnosis of heart disease is a reliable indicator, the computer may substantially improve our ability to diagnose effectively.